Pneumatic press



May 27, 1941. E. H. HALL PNEUMATIC PRESS Filed Oct. 1, 1958 Patented May27, 1941 UNITED TEES PATENT OFFICE v PNEUMATIC PRESS Edward H. Hall,Chicago, Ill.

Applicationoctober l, 1938, Serial No. 232,706

2 Claims.

My present invention relates to a press, such as is used in dieoperations, and more -particu larly to the employment therewith of apneumatic or hydraulic motor by which a slide is moved toward and from ahead whereby to apply to the work therebetween an even pressureirrespective of the distribution of the load.

A primary object of this invention is to devise in a press of thisgeneral character an operating mechanism with which a pneumatic (orhydraulic) motor may be used to greatest advantage. As a feature of theinvention I associate with such a motor a pair of opposed complementarytoggle mechanisms adapted to be operated simultaneously and in unisonupon release of a fluid force which is derived from any suitable source.More particularly, I have so arranged and organized the operating partsthat the force delivered by the pneumatic motor is directedsubstantially in the line of movement of the interconnections betweenthe several pairs of links which constitute the two opposed togglemechanisms, so as to utilize most effectively the mechanical force whichis delivered by the motor. In addition, the two sets of togglemechanisms are mechanically interconnected in such a way as to controltheir joint movements whereby movement of the slide proceeds evenly,irrespective of whether or not the load accommodated thereon be evenlydistributed. The

present operating mechanism may consist of parts which are simple,inexpensive, accessible and efiectively combined, all as suggested inthe accompanying drawing, wherein- Figure 1 is a perspective view of thepress in its entirety;

Fig. 2 is a vertical section through the press showing the positions ofthe operating parts when the slide is in lowermost position;

Fig. 3 which is a similar view shows the position of the operating partswhen the slide is in its uppermost position; and

Fig. 4 which is a View similar to Fig. 2, shows the motor joined to theopposed toggle mechanisms at the points of interconnection of theirrespective links rather than at a point slightly ofiset with respectthereto, as in the construction of the preceding figures.

In the exemplification shown, four guide rods G rise from a floor orbase to support at their upper ends a fixed head H. Mounted upon theguides for movement toward and from the head is a slide S whereon thework is adapted to be carried. To operate the slide in its up and downmovements I employ a pneumatic mechanism which is positioned between theslide and a fixed bed 13 therebelow;

Depending from the slide are two pairs of lugs 5 and B, one near eachcorner thereof, two pairs of oppositely positioned lugs 1 and 8 beingupstood from the bed therebelow. Pivotally joined at 10 to the lugs 5and 6 are a pair of links H which interconnect at l2 with a pair oflower links i3 joining pivotally at I 4 with the lower lugs 1. In likemanner at 20 a pair of links 2| are pivotally joined to the lugsfi,these links being interconnected at 22 to other lower links 23 which arepivotally joined at 24 to the lower lugs 8. One of the lower links I3 isprovided with an extension forming a crank arm 25 which at 26 ispivotally joined to a cross bar 2'! which is pivotally connected at 28to the opposite lower link 23. Since opposite ends of the cross barare'joined to opposed. lower links spaced from their points of pivotalconnection with the bed, any movement of either link is transmitted tothe other so that their movements are synchronized at all times.

To produce a lifting movement of the slide it is obvious that the twotoggle mechanisms should be moved in unison. The most effective way ofdoing this is to apply oppositely directed forces moving in a line whichproceed through the points 12 and 22 of the interconnection between theupper and lower links. This is especially important'when the slide is ina down position, as

in Fig. 2, because the toggle links then occupy a maximum angularposition relative to each other. The force requisite to straighten thelinks, even though proceeding in the line which intersects the twopoints of interconnection, must work to greatest disadvantage when thelifting movement first starts inasmuch as the angle of the toggle linksis then the greatest; partially or wholly compensating thisdisadvantage, however, is the fact that the slide, at the beginning ofits upward movement, is free to move without re- As the movementproceeds, however,

sistance. the toggle links will straighten up until finally at theconclusion of the movement (see Fig. 3) the links are in substantially astraight line position relative to each other. The operating forceapplied to the point of interconnection between the links becomes moreand more effective as the links approach this straight line position. Itis of chief importance, therefore, in the interests of successfuloperation, that the applied force be directed initially in a directionwhich is in line with the two points of interconnection between thelinks; it is of lesser importance, how

ever, that this force continue along the same line. According to theshowing of Figs. 1-3, the direction in which the force is applied dropsslightly below a line extending through the two points ofinterconnection between the links as the latter advance toward theirfinal straight position, whereas, according to Fig. 4, the operatingforce is applied always in the direction of this line.

The pneumatic motor herein shown comprises a cylinder to which is fittedat opposite ends heads and 3|, the latter being provided with an axialopening surrounded by a stufiing box 32 through which is extended a rod33 having connection with a piston 34 which is slidingly fitted withinthe cylinder. Air under pressure (or other fluid force) is admitted tothe cylinder at 35 at a point behind the piston, a flexible tube 36extending therefrom to a hand controlled threeway valve 31 which is inconnection with a source of fluid supply. By opening this valve thepiston is caused to advance from one end of the cylinder to the other,its return movement taking place when air is admitted, by propermanipulation of the valve, through another flexible tube 38 to theopposite cylinder end. Each operation of the valve will open a passagefor discharge of air at the piston side opposite that upon whichpressure is directed.

Extending from the cylinder head 30 is a lug 40 in pivotal connection asat 4| with a lug 42 piston rod which is extended exteriorly of thecylinder through the opposite head 3 I, is a fitting 43 having a pivotalconnection at 44 with 2. lug 45 that is extended laterally from thelower link l3 at a point relatively close to its interconnection l2 withthe upper link II. In the down position of the slide the two pivotalpoints 4| and 44 are substantially in line with the interconnectionpoints I2 and 22, so. thatthe force initially applied by movement ofthe'piston is in direct line therewith. As this movement proceeds thepneumatic motor moves down below the line which passes through theinterconnection points I 2 and 22, as best shown in Fig. 3, until at theconclusion of the movement the axis of the motor lies below this line aslight distance, as clearly represented in Fig. 3. It will be noted thata floating mounting is provided for the pneumatic motor so that it isfree to move up or down, depending upon whether the togglelinks aremoving from straight to angular positions, or vice versa. It will beobserved in these movements that the fixed bed B remains stationary.

The net result of operating the two sets of toggle mechanisms is toshift the vertical position of the slide toward or from the head so asto accomplish its intended work.

Referring now to Fig. 4, I have illustrated here two sets of togglemechanisms, the same as already described. The pneumatic motor, however,is supported pivotally at the interconnection points I2 and 22 so thatthe opposed forces which proceed therefrom are directed always in thesame line which extends between these points of interconnection, Such anarrangement has theoretical advantages, although for practical purposesthe efilciency is substantially the same as in the mechanism alreadydescribed. Where space is lacking, the arrangement of Fig. 4 may not bepossible, hence the advantage under such conditions of the lugs 42 and45 which extend laterally away from each other so as to provide betweenthem a space of increased length wherein a pneumatic motormay beaccommodated.

I claim: V I I 1. In a press having a bed, guides extending verticallyfrom the bed, a slide above the bed vertically movable along the guides,and a head above the slide in fixed relation to the bed, the combinationof a pair of transversely spaced toggle mechanisms for movingsaid slideeach comprising two laterally spaced hingedly connected pairs of linksjoined'respectively to the bed and slide, one of each of said pair ofsaid hingedly connected links having an out turned extension, atransversely expansible pneumatic motor extending between the opposedsides of said laterally spaced pairs of links and pivotally connected atits opposite ends to the outturned extensions thereof, and said pivotalconnections always lying in a plane intersecting the axis of thepneumatic motor, whereby during any operation of the slide the hingeconnections of said pairs of links will be in alignment with the pivotalconnections of the motor at the lowermost position of the slide only andbe entirely within the space between its pivotal connections with theopposite ends of Y said pneumatic motor and on opposite sides of saidmotor for carrying the motor therebetween. 2. The apparatus according toclaim 1 in which a synchronizing baris pivotally connected at itsopposite ends to one link of each pair of hingedly connected links only,so that in completely lowered position of the slide the link connectingone end of the bar will lie in a plane normal to the upper surface ofthe bed, and in completely raised position of the slidethe linkconnecting the opposite end of the bar will lie in a plane normal to theupper surface of the slide. 1

. EDWARD. H L.

